/*
    Color utilities.

    Copyright (C) 2005 Robert Lipe, robertlipe@usa.net

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111 USA

 */

#include "defs.h"

/*
 * Colors derived from http://www.w3.org/TR/SVG/types.html#ColorKeywords
 * which is also referenced in the CSS3 spec from w3.org as being the
 * same colors supported by X11.
 */

static const struct {
	const char *cn;
	unsigned char r;
	unsigned char g;
	unsigned char b;
} color_table[] = {
	{"aliceblue", 240, 248, 255},
	{"antiquewhite", 250, 235, 215},
	{"aqua",  0, 255, 255},
	{"aquamarine", 127, 255, 212},
	{"azure", 240, 255, 255},
	{"beige", 245, 245, 220},
	{"bisque", 255, 228, 196},
	{"black",  0, 0, 0},
	{"blanchedalmond", 255, 235, 205},
	{"blue",  0, 0, 255},
	{"blueviolet", 138, 43, 226},
	{"brown", 165, 42, 42},
	{"burlywood", 222, 184, 135},
	{"cadetblue",  95, 158, 160},
	{"chartreuse", 127, 255, 0},
	{"chocolate", 210, 105, 30},
	{"coral", 255, 127, 80},
	{"cornflowerblue", 100, 149, 237},
	{"cornsilk", 255, 248, 220},
	{"crimson", 220, 20, 60},
	{"cyan",  0, 255, 255},
	{"darkblue",  0, 0, 139},
	{"darkcyan",  0, 139, 139},
	{"darkgoldenrod", 184, 134, 11},
	{"darkgray", 169, 169, 169},
	{"darkgreen",  0, 100, 0},
	{"darkgrey", 169, 169, 169},
	{"darkkhaki", 189, 183, 107},
	{"darkmagenta", 139, 0, 139},
	{"darkolivegreen",  85, 107, 47},
	{"darkorange", 255, 140, 0},
	{"darkorchid", 153, 50, 204},
	{"darkred", 139, 0, 0},
	{"darksalmon", 233, 150, 122},
	{"darkseagreen", 143, 188, 143},
	{"darkslateblue",  72, 61, 139},
	{"darkslategray",  47, 79, 79},
	{"darkslategrey",  47, 79, 79},
	{"darkturquoise",  0, 206, 209},
	{"darkviolet", 148, 0, 211},
	{"deeppink", 255, 20, 147},
	{"deepskyblue",  0, 191, 255},
	{"dimgray", 105, 105, 105},
	{"dimgrey", 105, 105, 105},
	{"dodgerblue",  30, 144, 255},
	{"firebrick", 178, 34, 34},
	{"floralwhite", 255, 250, 240},
	{"forestgreen",  34, 139, 34},
	{"fuchsia", 255, 0, 255},
	{"gainsboro", 220, 220, 220},
	{"ghostwhite", 248, 248, 255},
	{"gold", 255, 215, 0},
	{"goldenrod", 218, 165, 32},
	{"gray", 128, 128, 128},
	{"grey", 128, 128, 128},
	{"green",  0, 128, 0},
	{"greenyellow", 173, 255, 47},
	{"honeydew", 240, 255, 240},
	{"hotpink", 255, 105, 180},
	{"indianred", 205, 92, 92},
	{"indigo",  75, 0, 130},
	{"ivory", 255, 255, 240},
	{"khaki", 240, 230, 140},
	{"lavender", 230, 230, 250},
	{"lavenderblush", 255, 240, 245},
	{"lawngreen", 124, 252, 0},
	{"lemonchiffon", 255, 250, 205},
	{"lightblue", 173, 216, 230},
	{"lightcoral", 240, 128, 128},
	{"lightcyan", 224, 255, 255},
	{"lightgoldenrodyellow", 250, 250, 210},
	{"lightgray", 211, 211, 211},
	{"lightgreen", 144, 238, 144},
	{"lightgrey", 211, 211, 211},
	{"lightpink", 255, 182, 193},
	{"lightsalmon", 255, 160, 122},
	{"lightseagreen",  32, 178, 170},
	{"lightskyblue", 135, 206, 250},
	{"lightslategray", 119, 136, 153},
	{"lightslategrey", 119, 136, 153},
	{"lightsteelblue", 176, 196, 222},
	{"lightyellow", 255, 255, 224},
	{"lime",  0, 255, 0},
	{"limegreen",  50, 205, 50},
	{"linen", 250, 240, 230},
	{"magenta", 255, 0, 255},
	{"maroon", 128, 0, 0},
	{"mediumaquamarine", 102, 205, 170},
	{"mediumblue",  0, 0, 205},
	{"mediumorchid", 186, 85, 211},
	{"mediumpurple", 147, 112, 219},
	{"mediumseagreen",  60, 179, 113},
	{"mediumslateblue", 123, 104, 238},
	{"mediumspringgreen",  0, 250, 154},
	{"mediumturquoise",  72, 209, 204},
	{"mediumvioletred", 199, 21, 133},
	{"midnightblue",  25, 25, 112},
	{"mintcream", 245, 255, 250},
	{"mistyrose", 255, 228, 225},
	{"moccasin", 255, 228, 181},
	{"navajowhite", 255, 222, 173},
	{"navy",  0, 0, 128},
	{"oldlace", 253, 245, 230},
	{"olive", 128, 128, 0},
	{"olivedrab", 107, 142, 35},
	{"orange", 255, 165, 0},
	{"orangered", 255, 69, 0},
	{"orchid", 218, 112, 214},
	{"palegoldenrod", 238, 232, 170},
	{"palegreen", 152, 251, 152},
	{"paleturquoise", 175, 238, 238},
	{"palevioletred", 219, 112, 147},
	{"papayawhip", 255, 239, 213},
	{"peachpuff", 255, 218, 185},
	{"peru", 205, 133, 63},
	{"pink", 255, 192, 203},
	{"plum", 221, 160, 221},
	{"powderblue", 176, 224, 230},
	{"purple", 128, 0, 128},
	{"red", 255, 0, 0},
	{"rosybrown", 188, 143, 143},
	{"royalblue",  65, 105, 225},
	{"saddlebrown", 139, 69, 19},
	{"salmon", 250, 128, 114},
	{"sandybrown", 244, 164, 96},
	{"seagreen",  46, 139, 87},
	{"seashell", 255, 245, 238},
	{"sienna", 160, 82, 45},
	{"silver", 192, 192, 192},
	{"skyblue", 135, 206, 235},
	{"slateblue", 106, 90, 205},
	{"slategray", 112, 128, 144},
	{"slategrey", 112, 128, 144},
	{"snow", 255, 250, 250},
	{"springgreen",  0, 255, 127},
	{"steelblue",  70, 130, 180},
	{"tan", 210, 180, 140},
	{"teal",  0, 128, 128},
	{"thistle", 216, 191, 216},
	{"tomato", 255, 99, 71},
	{"turquoise",  64, 224, 208},
	{"violet", 238, 130, 238},
	{"wheat", 245, 222, 179},
	{"white", 255, 255, 255},
	{"whitesmoke", 245, 245, 245},
	{"yellow", 255, 255, 0},
	{"yellowgreen", 154, 205, 50},
};


/*
 * Functions for converting human-readable colors to BBGGRR value.
 * Substantial optimization opportunities remain.
 */
static int HexDigit( char hex ) {
	const char *Digits = "0123456789ABCDEF";
	const char *digits = "0123456789abcdef";
	char * ofs = strchr( digits, hex );
	if ( ofs ) {
		return ofs-digits;
	}
	
	ofs = strchr( Digits, hex );
	if ( ofs ) {
		return ofs-Digits;
	}
	return 0;
}

static int HexByte( const char* hex ) {
	int b =  (HexDigit(hex[0])<<4)+HexDigit(hex[1]);
	return b;
}

/*
 * Given an input of the form:
 *   #<hex number for RGB value>
 *   <decimal nummber for BBGGRR value>
 *   <color named in CSS1 spec>
 * return the BBGGRR value for it.
 */
 
int
color_to_bbggrr( const char *opt_color ) 
{
	int color_num;
	unsigned int i;
	char *ep;
	
	color_num = strtol(opt_color, &ep, 10);

	if (ep != opt_color) {
		return color_num;
        } 

	if ( opt_color[0] == '#' ) {
		color_num = (HexByte( opt_color+1 )) +    // red
			        (HexByte( opt_color+3 )<<8) + // green
				(HexByte( opt_color+5 )<<16); // blue
		return color_num;
	}

	for (i = 0; i < sizeof(color_table) / sizeof(color_table[0]); i++) {
		if (0 == case_ignore_strcmp(opt_color, color_table[i].cn)) {
			return (color_table[i].b << 16) + 
				(color_table[i].g << 8) + 
				color_table[i].r;
		}
	}

	fatal( "unrecognized color name %s\n", opt_color );
	return -1;
}
